The militant East Turkestan Islamic Movement organised the suicide vehicle attack that killed five people in the heart of Beijing this week, China's most senior security official said.
He was speaking from Tashkent, the capital of Uzbekistan, where he was attending a regional security summit and seeking co-operation in counter-terrorism.
"The violent terrorist incident that happened in Beijing is an organised and plotted act," he said.
"Behind the instigation is the terrorist group East Turkestan Islamic Movement entrenched in central and west Asian regions," he said, in a video footage aired yesterday by Phoenix Television.
He did not provide further detail, and the alleged terrorist group has not made a claim of responsibility.
An SUV ploughed through bystanders, crashed and burst into flames near the Tiananmen Gate on Monday, killing three in the car and two tourists, including a Filipino woman, and injuring dozens.
Beijing police said the perpetrators were a man with an ethnic Uighur name, his wife and his mother. Police also have arrested five people - identified with typically Uighur names - on suspicion of conspiring in the attack and called it a planned terror strike - the city's first in recent history.
Knives, iron rods, petrol and a flag imprinted with religious slogans were found in the vehicle, police said.
China believes the East Turkestan Islamic Movement aims to establish an independent East Turkestan in Xinjiang, and blames the group for the low-intensity insurgency in the region.
The US placed the movement on a terrorist watch list following the September 11 attacks, but quietly removed it amid doubts that it existed in any organised manner.
Instead, human rights groups question whether China uses the security threat as an excuse to suppress the Uighurs and say Uighur extremism has been fuelled by China's heavy-handed policies in Xinjiang and discrimination against Uighurs by the country's ethnic Han majorities.
Uighurs say they have seen little benefit from the exploitation of Xinjiang's natural resources while good jobs tend to flow to ethnic Han migrants.
The 9 million Uighurs now make up about 43% of the population in a region more than twice the size of Texas where they used to dominate.
Following Monday's attack, police have set up checkpoints and stepped up security in Xinjiang , according to various reports.